André Meheus

Epidemics of syphilis in the Russian Federation: trends, origins, and priorities for control

After continuous decline throughout the 1980s, surveillance-defined estimates of the incidence of syphilis in Russia have shown a rapid and substantial increase during the 1990s. The reasons for this epidemic are unclear, but must be sought among changes both in sexual behaviour and in the patterns of provision, use, and effectiveness of diagnostic, treatment, and contact tracing services. High incidence of sexually transmitted disease causes correspondingly high levels of morbidity and suffering as well as significant health-care and other economic costs. Our current understanding suggests that the transmissibility of HIV is increased by infection with sexually transmitted disease. The syphilis epidemic together with changes in sexual behaviour, increased travel and migration, and rapid increases in injecting drug use may create the conditions for an epidemic of sexually acquired HIV infection in Russia that substantially outstrips those encountered in most Western European countries.

Safety and immunogenicity of a hepatitis B vaccine formulated with a novel adjuvant system

A formulation of recombinant hepatitis B surface antigen (HBsAg) combined with a novel adjuvant system, SBAS4--a combination of aluminium salt and monophosphoryl lipid A (MPL), was assessed in 27 healthy adult volunteers with a commercial vaccine (Engerix-B) as control. After three doses (0, 1, 6 months schedule), reactogenicity profiles were similar. Local reactions were essentially mild, the most frequent being soreness at the injection site. Seroprotection was achieved after two doses in all subjects given the candidate vaccine, all Engerix-B vaccines being seroprotected after the third dose. After the second and third doses, higher anti-HBs Geometric Mean Titres (GMTs) were observed in the group which received the formulation with the novel adjuvant system, and cellular immunity, measured as HBsAg-specific lymphoproliferation was stronger than with Engerix-B. These results indicate that the new formulation is safe, well-tolerated and immunogenic and may promote more rapid protection against hepatitis B infection.

Integration of hepatitis B vaccination into national immunisation programmes

Abstract Hepatitis B is a major public health problem even though safe and effective vaccines have been available for over 10 years. Because hepatitis B infection is largely asymptomatic with long term complications occurring after many years it has not received the attention it deserves. Strategies to immunise those at high risk have failed to control the disease. Delegates to the World Health Assembly of the World Health Organisation recommended in May 1992 that all countries should integrate hepatitis B vaccination into their national immunisation programmes by 1997. Some western European countries remain unconvinced that the burden of disease warrants the expense of universal vaccination. However, epidemiological data and economic evaluation show that universal hepatitis B vaccination is cost effective in countries with low endemicity and that it will control hepatitis B, reinforcing the necessity for action.

The endemic treponematoses.

Treponemal diseases comprise venereal syphilis (Treponema pallidum subsp. pallidum) and the endemic (non-venereal) treponematoses, i.e. yaws (T. pallidum subsp. pertenue), endemic syphilis (T. pallidum subsp. endemicum) and pinta (T. carateum). Treponemal diseases are distinguished on the basis of epidemiological characteristics and clinical manifestations. They are at present indistinguishable by morphological, immunological or serological methods. Several minor genetic differences have been identified among the subspecies. The endemic treponematoses have not yet been eliminated and are currently thought to affect at least 2.5 million persons. Renewed action towards the elimination of these diseases should be undertaken.

Hepatitis B virus and human immunodeficiency virus co-infection in sub-Saharan Africa: a call for further investigation.

Abstract: A growing body of evidence indicates that human immunodeficiency virus (HIV)‐positive individuals are more likely to be infected with hepatitis B virus (HBV) than HIV‐negative individuals, possibly as a result of shared risk factors. There is also evidence that HIV‐positive individuals who are subsequently infected with HBV are more likely to become HBV chronic carriers, have a high HBV replication rate, and remain hepatitis Be antigen positive for a much longer period. In addition, it is evident that immunosuppression brought about by HIV infection may cause reactivation or reinfection in those previously exposed to HBV. Furthermore, HIV infection exacerbates liver disease in HBV co‐infected individuals, and there is an even greater risk of liver disease when HIV and HBV co‐infected patients are treated with highly active anti‐retroviral therapy (HAART). Complicating matters further, there have been several reports linking HIV infection to ‘sero‐silent’ HBV infections, which presents serious problems for diagnosis, prevention, and control. In sub‐Saharan Africa, where both HIV and HBV are endemic, little is known about the burden of co‐infection and the interaction between these two viruses. This paper reviews studies that have investigated HIV and HBV co‐infection in sub‐Saharan Africa, against a backdrop of what is currently known about the interactions between these two viruses.

Vaccine Safety Controversies and the Future of Vaccination Programs

In the years following the hepatitis B vaccination/multiple sclerosis controversy, a number of new issues regarding vaccine safety have been raised, in some cases leading to more debate and confusion. Against this background, an international group of experts was convened to review the current points of view concerning the use of thimerosal as a preservative and its potential risks; the suggested link between thimerosal-containing vaccines and acute lymphoblastic leukemia; the alleged association between aluminum-containing vaccines/macrophagic myofasciitis and general systemic complaints; a possible link between vaccination and autoimmune pathology; and a hypothetical link between measles-mumps-rubella vaccination and autism. At present, there are no data to conclude that childhood vaccines, and in particular hepatitis B vaccine, pose a serious health risk or justify a change in current immunization practice. However, vaccine “scares” continue to have an international impact on immunization coverage. Creating a positive environment for immunization can be achieved by repositioning the value of vaccines and vaccination, supported by evidence-based information. The role of international organizations, the media, and the industry in the implementation of communication strategies was discussed and the impact of litigation issues on vaccination was evaluated. The Viral Hepatitis Prevention Board confirms its commitment to current recommendations for universal and risk group hepatitis B vaccination and further encourages the conduct of vaccine safety studies and the dissemination of their results.

Maternal and congenital syphilis programmes: case studies in Bolivia, Kenya and South Africa

Preventing congenital syphilis is not technically difficult, however operational difficulties limit the effectiveness of programmes in many settings. This paper reports on programmes in Bolivia, Kenya, and South Africa. All three countries have established antenatal syphilis control programmes. Early antenatal syphilis screening and management of positive cases were difficult to implement since most women presented for their first antenatal clinic visit after 6 months of pregnancy. Most women had rapid plasma reagin (RPR) testing; results were available on the same day in some clinics but took up to 4 weeks in others. No clinic had a system for tracking RPR-reactive women who did not return for their results. There were no guidelines for providers in Kenya and Bolivia. In all countries, supplies, drugs, notification cards, and other consumables were often unavailable. Health-care providers were unmotivated in Kenya and reported an excessive client load. In South Africa and Kenya some clients reported at their exit interview that they had never heard of syphilis nor had they been informed why blood was collected. Several prevention strategies could be implemented at the clinic level. These include encouraging women to attend for antenatal care before the fourth month of pregnancy, providing point-of-care testing so that results are available immediately and women who test positive can be treated, implementing presumptive treatment of sexual partners of women who test positive, adding a second test later in pregnancy so that incident cases can be managed, and improving the quality of syphilis care during pregnancy, delivery, and the neonatal period.

Hepatitis B virus vaccination and antenatal transmission of HBV markers to neonates.

The high prevalence of hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) in pregnant women is considered to be the most important factor contributing to the high carrier rate of HBsAg in some populations. Several factors, including the age at which infection occurs, predispose to the acquisition and frequency of the carrier state. The proportion of infected people who become chronic carriers ranges from about 80 to 95% for babies born to HBsAg/HBeAg‐positive mothers. In this study of Indonesian infants receiving only active immunization against HBV, we measured the HBV markers passively acquired from their HBsAg‐positive mothers. The relationship of these markers with vaccination response and with HBV infection status was studied longitudinally in the infants. In the exposed neonates from the HBsAg‐positive mothers (n=61), the seroconversion rate to hepatitis B surface antibody (HBsAb) positivity was 95% after the first booster vaccination, with a geometric mean titre (GMT) of 2017IUl–1. After 60months, the GMT in this group decreased to 50IUl–1. Four newborns in this group became HBsAg carriers. Of the four vaccination failures, three newborns were HBsAg/HBeAg positive at birth, suggesting that they had been infected in utero. No vaccination strategy (active alone, or passive/active) can prevent this transmission from occurring. One carrier was HBsAg negative at birth and up to month 4 but was HBsAg positive at month 12 and subsequently, suggesting a postnatal infection. Vaccination early in life can, to a large extent, prevent perinatal transmission and hepatitis B virus (HBV) infection later in infancy and childhood. In this study, the protective efficacy of the vaccination was 85% in the subcohort of neonates from HBeAg‐positive mothers and 100% in the subcohort of neonates from HBeAg‐negative mothers. Lack of maternal antibodies to hepatitis B core antigen (HBcAb) correlated strongly with transmission of HBV infection.

Chlamydial infection: an accurate model for opportunistic screening in general practice

Objectives: To estimate the prevalence of Chlamydia trachomatis in women in general practice and to assess risk factors associated with infection. Methods: The study was carried out in 2001–2 in different general practices in Antwerp, Belgium. Sexually active women, visiting their general practitioner for routine gynaecological care (mostly pill prescription or PAP smear), were offered opportunistic screening for chlamydia. 787 participants aged 15–40 delivered a self taken vaginal sample and filled in a questionnaire which included questions on demographic variables, urogenital symptoms, sexual history, and sexual behaviour. Samples were tested for presence of chlamydial DNA by means of a ligase chain reaction (LCR) assay, and positives were confirmed by two other amplification assays (PCR and SDA). Results: Overall prevalence was 5.0% (95% CI: 3.5 to 6.5). Determinants of infection in logistic regression analysis were age 18–27 years, >1 partner in the past year, no use of contraceptives, frequent postcoital bleeding, having a symptomatic partner, painful micturition, and living in the inner city. The area under the ROC curve in the full model was 0.88. Selective screening based on a combination of the five first determinants detects 92.3% of infections in this sample; 37.5% of the population would need to be screened. Conclusion: Targeted screening for chlamydial infection is possible, even in a heterogeneous group of general practice attendants. Implementing this model would require considerable communication skills from healthcare providers.

Prevention of hepatitis C virus infection

In spite of advances made in our understanding of the biology of the hepatitis C virus (HCV), the epidemiology and natural history of HCV infection, and the treatment of chronic hepatitis C, the development and worldwide implementation of a comprehensive prevention and control strategy remains necessary. A World Health Organization informal consultation with the Viral Hepatitis Prevention Board was convened and met in Geneva, Switzerland, 13–14 May 2002, to review epidemiological and public health aspects of HCV infection, and the various prevention and control strategies that are currently in place. Based on the presentations and discussions, a number of specific recommendations were made, which should be considered in conjunction with previously published recommendations.